European seismic prequalification of steel beam-to-column joints: EQUALJOINTS and EQUALJOINTS-Plus projects

EQUALJOINTS and EQUALJOINTS-Plus are two European projects (research and dissemination respectively) funded by the European Research fund for Coal and Steel (RFCS) and coordinated by the Author. The main aim of these projects was to develop seismic prequalification procedures, currently missing in EN1998-1:2005, for the beam-to-columns joints that are most commonly used in the EU practice, namely unstiffened, haunch- and ribstiffened bolted end-plate joints as well as welded dog-bone. To achieve this purpose, a wide range of experimental tests, numerical simulations and analytical investigations were carried out. Design tools and prequalification charts were developed to support the use of prequalified joints among designers and fabricators. These charts include general requirements, limitations, a step-by-step design procedure and qualification data, which have also provided the technical and scientific background required to introduce the rules for prequalified joints in the 2nd generation of Eurocode 8. The obtained results were disseminated through 14 workshops and seminars over Europe and United States of America. In this paper the research activity carried out in both projects as well as the relevant main achievements are presented and discussed.